An internal combustion engine includes a combustion chamber, where a fuel air mixture is burned to cause movement of a set of reciprocating pistons, and a crankcase, which contains the crankshaft driven by the pistons. During operation, it is normal for the engine to experience “blow-by,” wherein combusted engine gases leak past the piston-cylinder gap from the combustion chamber and into the crankcase. These blow-by or crankcase gases contain moisture, acids and other undesired by-products of the combustion process.
It is normal for crankcase gases to also include a very fine oil mist. The oil mist escapes from the engine to the manifold. The oil mist is then carried from the manifold back into the combustion chamber along with the fuel/air mixture. This results in an increase in oil consumption. Additionally the combustion of the oil mist causes a build-up of residuals in the combustion chamber and on pistons which over time decreases engine efficiency. An engine typically includes a Positive Crankcase Ventilation (PCV) system for removing these harmful gases from the engine and prevents those gases from being expelled into the atmosphere. It is known to incorporate an oil separating device in a PCV system to remove oil from these crankcase gases. It is known to use manifold vacuum to draw crankcase gases into localized high velocity areas of the oil separator to promote separation of oil from the gases. The oil is re-introduced back to a sump via a drain device which is located generally at the bottom of the oil separator to allow for gravity to assist the drainage of oil. The sump generally holds excess oil in the system.
However, during certain engine operating conditions such as when the engine is operating at a wide open throttle, there is not enough manifold vacuum to draw the crankcase gases. Accordingly some oil separating devices use auxiliary power to draw the crankcase gases. For instance, some oil separating devices use a centrifugal oil separator to draw crankcases gases and separate the oil from those gases. Such devices use a rotary component driven by a motor or a turbo transmission. However the such centrifugal oil separators do not capture oil, rather oil is separated from the crankcase gases and collected. Yet other oil separating devices with a rotary component include a shaft and a spiraling member spiraling along the shaft. The spiraling component defines a uniformly shaped passage interconnecting the inlet to an outlet. The cyclone effect created by these devices thrusts the crankcase gases against a wall whereby the oil is separated oil from crankcase gases. Such devices do not compress the crankcase gases, rather the separated oil is splattered against and collects on the inner wall of the housing and drains to the engine.
However, micron and sub-micron particles of oil remain in the crankcase gases. Accordingly, it remains desirable to provide an improved device that is more efficient than conventional oil separator designs in capturing micron and sub-micron particles of oil from crankcase gases while at the eliminating reliance upon manifold vacuum to draw crankcases gases.